Hello. I have six sprinklers in a single zone, and when triggered by my timer to start, they do not pop up all the way and water just spills out from the heads without spraying. However, when I step on one of the heads (any of the six), they all then pop up and then start working properly. I had the irrigation company come over and take a look. They said it was a faulty valve for that zone, which they replaced. However, after they left, the issue still persists. Does anyone have any insight on what the issue could be? All the other zones work fine, and like I mentioned, when I step on the sprinkler head, they start working, so I'm thinking it's not a water pressure issue. Thank you in advance.